Determination of Phenolic Anti-Oxidants in Edible Oil by High-Performance Liquid Chromatography with Amperometric Detector

Abstract

A high-performance liquid chromatography (HPLC) with amperometric detection was investigated for the analysis of 2-and 3-tert-butyl-4-hydroxyanisole (BHA), 3,5-di-tert?butyl-4-hydroxytoluene (BHT), and tert?butyl-hydroquinone (TBHQ) in edible oil. The reversed-phase system developed was combined with an amperometric detector, the working electrode of which was made of glassy carbon, in order to compare the sensitivity and selectivity of ultraviolet and fluorometric detection. For the amperometric detection of HPLC, cyclic voltammetry was used to monitor the electrochemical properties of the phenolic antioxidants. A simple isolation procedure, based on the continuous liquid-liquid partition technique, was examined for the extraction and clean up of the antioxidants from edible oil. The recovery rates of BHA, BHT, and TBHQ added salad oil were between 90.2-107.7% in the range of 1-50 ppm of the antioxidants. By the present method, BHA, BHT, and TBHQ were well separated, identified and quantitated with a high sensitivity.     

Determination of synthetic phenolic antioxidants in essence perfume by high performance liquid chromatography with vortex-assisted,cloud-point extraction using AEO-9

This study aimed to establish a rapid analytical method to determine antioxidants in essence. A simple,efficient and practical, vortex-assisted, cloud-point extraction(VACPE) procedure is proposed for extracting and pre-concentrating four different of synthetic phenolic antioxidants(SPAs), propyl gallate(PG), tert-butylhydroquinone(TBHQ), butylated hydroxyanisole(BHA), butylated hydroxytoluene(BHT) in essence prior to high performance liquid chromatography(HPLC) analysis. The non-ionic surfactant, fatty alcohol polyoxyethylene ether-9(AEO-9), was used as extractant and vortex-mixing was utilized to reduce extraction time and improve extraction efficiency. The effective parameters of the extraction process, such as volume of extraction solvent, pH, vortex-mixing time, equilibration temperature and time, were optimized. Under the optimum conditions, the linear range of PG, TBHQ,BHA and BHT was 8.0–800 ng/mL. All correlation coefficients of the calibration curves were higher than0.996 and relative standard deviations(RSD, n = 5) were 2.36%–5.46%. The proposed method was successfully applied to the extraction and determination of antioxidants in essence samples with satisfactory relative recoveries of 89.4%–103.5%. The results confirmed the SPAs of essence could be effectively monitored by this method and also established good reference criteria for essence.     

Glassy carbon electrodes modified with gold nanoparticles for the simultaneous determination of three food antioxidants

Electrochemical behavior of three antioxidants: butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and butylated hydroquinone (TBHQ), was investigated at a glassy carbon electrode modified with gold nanoparticles (AuNPs/GCE). This electrode was characterized by scanning electron microscopy (SEM). The experimental results indicated that the modified electrode was strongly electroactive during the redox reactions of BHA, BHT and TBHQ, and this was confirmed by the observed increased redox peak currents and shifted potentials; in addition, the oxidation products of BHA and TBHQ were found to be the same. The experimental conditions were optimized and the oxidation peaks of BHA and BHT were clearly separated. Based on this, an electrochemical method was researched and developed for the simultaneous determination of BHA, BHT and TBHQ in mixtures with the use of first derivative voltammetry; the linear concentration ranges were 0.10–1.50 μg mL⁻¹, 0.20–2.20 μg mL⁻¹ and 0.20–2.80 μg mL⁻¹, and detection limits were 0.039, 0.080 and 0.079 μg mL⁻¹, for BHA, BHT and TBHQ, respectively. The proposed method was successfully applied for the analysis of the three analytes in edible oil samples.     

毛细管气相色谱法测定食用油中的酚类抗氧化剂BHA、BHT、TBHQ

建立了同时测定植物油中BHA、BHT、TBHQ等3种酚类抗氧化剂的测定方法。样品中的抗氧化剂经石油醚提取、乙腈萃取后采用HP-5毛细管柱分离。样品加标回收率为82.8?.6%,相对标准偏差为1.06%~3.11%,BHA、BHT、TBHQ的最低检出量分别为5、10、5ng。该方法具有快速、灵敏度高、重现性好、前处理简单等优点。     

Determination of antioxidants in cosmetics by micellar electrokinetic capillary chromatography with electrochemical detection

A new and efficient method for the determination of antioxidants [Propyl gallate (PG), tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT)] in cosmetics has been established by using micellar electrokinetic capillary chromatography with electrochemical detection (MECC-ED). Under the optimum conditions of the method, all analytes were successfully separated within 13 min at the separation voltage of 18 kV in a 20 mmol/L borate running buffer (pH 7.4) containing 25 mmol/L sodium dodecyl sulfate. The excellent linearity was obtained in the concentration range from 5.0 x 10(-4) to 2.0 x 10(-6) mol/L and the detection limits (S/N = 3) of PG, TBHQ, BHA, and BHT range from 3 x 10(-7) to 3 x 10(-6) mol/L.     

气相色谱法测定高分子食品包装材料中抗氧化剂的残留量

建立了气相色谱测定高分子食品包装材料中抗氧化剂丁基羟基茴香醚(BHA)、二丁基羟基甲苯(BHT)和特丁基对苯二酚(TBHQ)残留量的分析方法。用环己烷超声萃取高分子食品包装材料样品,考察了萃取时间、温度对抗氧化剂萃取量的影响。萃取液经气相色谱柱HP-50+毛细管柱(30 m×0.53 mm×1 μm)分离,电子捕获检测器(ECD)检测,外标法定量。结果表明: 在抗氧化剂添加量为3.00～10.0 mg/kg范围内,BHT、BHA、TBHQ在高分子食品包装材料中的平均添加回收率分别为88%～93%、92%～101%和83%～97%,相对标准偏差(RSD, n=5)分别为2.01%～2.89%、2.11%～3.19%和2.99%～4.02%;检出限(信噪比为3)分别为0.5、0.5和0.8 mg/kg。对实际高分子食品包装材料样品的检测结果表明3种抗氧化剂在不同材质中均有检出: 塑料材料中抗氧化剂的含量较少,仅有BHT、BHA被检出,含量为6.3～7.8 mg/kg;橡胶材料中3种抗氧化剂均被检出,含量为9.3～28.4 mg/kg。该方法准确、灵敏、重现性好,适用于高分子食品包装材料中抗氧化剂残留量的检测。     

高效液相色谱法同时测定食用油脂和膨化食品中的3种抗氧化剂

建立同时测定食用油脂和膨化食品中3种抗氧化剂丁基羟基茴香醚(BHA)、二丁基羟基甲苯(BHT)、特丁基对苯二酚(TBHQ)的高效液相色谱法.样品经甲醇提取后,以甲醇-0.1%甲酸溶液为流动相梯度洗脱,C18色谱柱分离,采用高效液相色谱法(HPLC)-二极管阵列检测器(DAD),在检测波长280 nm,参比波长360 n...     

Simultaneous determination of five synthetic antioxidants in edible vegetable oil by GC–MS

A simple, quick and nontoxic analytical method for the simultaneous determination of five synthetic antioxidants [t-butyl-4-hydroxyanisole (BHA), 2,6-di-t-butyl-hydroxytoluene (BHT), t-butyl hydroquinone (TBHQ), ethoxyquin (EQ) and 2,6-di-tert-butyl-4-hydroxymethyl-phenol (Ionox 100)] in edible vegetable oil has been developed. The analytes were extracted by ethanol, then separated and detected by GC–MS. Extraction conditions such as volume of ethanol required, mixing time and number of extractions were investigated and optimized by an orthogonal array experimental design. The five compounds behaved linearly in the 0.100∼20.0 mg/L concentration range, and the limits of detection (LOD) for BHA, BHT, TBHQ, EQ and Ionox-100 were 1.00, 0.92, 11.5, 0.83 and 1.39 μg/L, respectively. The recoveries at the tested concentrations of 1.00, 20.0 and 100 mg/kg were 75.6∼123%, with coefficients of variation <10.0%. The proposed procedure was successfully applied to the simultaneous analysis of the five antioxidants in soybean oil, tea oil, edible blended oil, rap oil, peanut oil, peanut blended oil and sesame oil samples purchased from local supermarkets.     

Voltammetric determination of the phenolic antioxidants 3-tert-butyl-4-hydroxyanisole and tert-butylhydroquinone at a polypyrrole electrode modified with a nickel phthalocyanine complex

The voltammetric behaviour of the antioxidants 3-tert-butyl-4-hydroxyanisole (BHA) and tert-butylhydroquinone (TBHQ), at a polymer electrode modified with nickel phthalocyanine as electron mediator, is described, and an electroanalytical method for the determination of these antioxidants based on their electrochemical oxidation on the modified electrode is proposed. Cyclic voltammograms showed well-defined oxidation peaks slightly shifted towards less positive potentials with respect to those obtained at the platinum disk electrode for both antioxidants. The peak currents measured at the modified electrode are considerably higher than those obtained at the unmodified electrode. A scan rate of 100 mV s(-1), a minimum methanol percentage of 0.5% and a 0.1-M Britton-Robinson medium were chosen as working conditions. The obtained results suggest that the BHA oxidation produces the TBHQ reduction product. This product is oxidised during the second cyclic scan, to generate the mentioned TBHQ as final product. These studies also reveal that sensitive response for both antioxidants can be obtained by using the differential pulse voltammetry (DPV) technique. Responses observed are dependent on the nature of the control solution (% methanol and pH) and the nature of voltammetric conditions (potential amplitude, DeltaE, and scan rate, v(b)). These factors have been modified in order to find the best analytical conditions. The mutual interferences between both antioxidants and the measurement reproducibility were tested. Using cyclic voltammetry (CV) and differential pulse voltammetry, BHA and TBHQ linear calibration graphs were obtained. The detection limits were 2.1 ppm for both when CV was used, and 18.7 ppm (BHA) and 1.23 ppm (TBHQ) for DPV. The developed methods were applied to the determination of BHA in spiked glaze biscuits and TBHQ in spiked mushroom cream.     

固相萃取-高效液相法测定炒货食品及坚果制品中的多种抗氧化剂

运用固相萃取和高效液相色谱技术,建立炒货食品及坚果制品中丁基羟基茴香醚(BHA)、二丁基羟基甲苯(BHT)、叔丁基对苯二酚(TBHQ)、没食子酸丙酯(PG)等人工合成的抗氧化剂和茶多酚、甘草抗氧化物、迷迭香提取物等天然抗氧化剂的测定方法。样品经甲醇、异丙醇、乙腈等混合溶剂提取,冷冻离心后经C18柱固相萃取净化,用高效液相色谱检测。各抗氧化剂残留量在6~100 mg/L范围内呈良好线性关系,加标回收率为80%~106%。     

A Sensitive Sensor Based on CuTSPc and Reduced Graphene Oxide for Simultaneous Determination of the BHA and TBHQ Antioxidants in Biodiesel Samples

A novel and sensitive electrochemical sensor was developed for the simultaneous determination of the butylated hydroxyanisole (BHA) and tert‐butylhydroquinone (TBHQ) antioxidants in biodiesel samples employing the differential pulse voltammetry (DPV). In this sense, a glassy carbon electrode (GCE) modified with copper (II) tetrasulfonated phthatocyanine immobilized on reduced graphene oxide (CuTSPc/rGO) allowed the detection of BHA and TBHQ at potentials lower than those observed at unmodified electrodes. The sensor was characterized by cyclic voltammetry (CV) and linear scan voltammetry (LSV). After optimization of the experimental parameters, the analytical curves for simultaneous determination of BHA and TBHQ by DPV technique demonstrated an excellent linear response from 0.1 to 500 µmol L^?1 with detection limit of 0.045 µmol L^?1 for TBHQ and 0.036 µmol L^?1 for BHA. Finally, the proposed method was successfully applied in the simultaneous determination of BHA and TBHQ in six biodiesel samples, and the results obtained were found to be similar to those obtained using the HPLC method with agreement at 95 % confidence level.     

Feasibility of a Nano‐Carbon Black Paste Electrode for Simultaneous Voltammetric Determination of Antioxidants in Food Samples and Biodiesel in the Presence of Surfactant

In this work, a simple and low‐cost method was developed for the simultaneous determination of the antioxidants tert‐butylhydroquinone (TBHQ) and butylated hydroxyanisole (BHA) in the presence of the cationic surfactant CPB by square wave voltammetry (SWV) technique using a carbon black paste electrode (CBPE). The performance of the method was investigated by varying parameters such as pH, electrolyte, and type and concentration of surfactant. Under the optimum conditions of 0.2 mol L^?1 phosphate buffer (pH 7.0), 600.0 μmol L^?1 of cetylpyridinium bromide surfactant and SWV operating parameters optimized through the Doehlert matrix, the method presented low limits of quantification for TBHQ and BHA (0.23 and 0.26 μmol L^?1, respectively) and high precision in successive measurements. The proposed method was applied in mayonnaise, margarine and biodiesel and the accuracy of method was checked by the HPLC technique.     

Analyses of synthetic antioxidants by capillary electrochromatography using poly(styrene-divinylbenzene-lauryl methacrylate) monolith

In this study, several organic polymer-based monoliths prepared by single step in situ copolymerization of styrene- and methacrylate ester-based monomers (styrene (S), divinylbenzene (DVB) and lauryl methacrylate (LMA)) were developed as stationary phases of capillary electrochromatography (CEC) for the analyses of synthetic antioxidants. These monoliths were characterized by examining the SEM image, IR spectrum, and measuring the pore size, surface area, conversion yield, and thermal decomposition temperature. The polymerization procedure was optimized by varying the reaction temperature, the reaction time, and the LMA-styrene ratio. The LMA-styrene ratio had the most significant influence on the peak symmetry of butylated hydroxyanisole (BHA) and 2, 6-di-tert-butyl-4-methyl phenol (BHT), the latter being greatly affected by excessive peak tailing in the poly(S-DVB) monolith. It showed that the interaction between the poly(S-DVB) monolith and the antioxidant (BHT or BHA) was significantly altered by the insertion of LMA. Compared with the best HPLC and CE methods previously reported, this proposed CEC method provides a comparable separation ability for the five antioxidants analyzed. This study demonstrates that the potentiality of poly(S-DVB-LMA) monolith as stationary phase, especially for CEC system, because of high thermal stability and good column reproducibility.     

Electrochemical study of antioxidants at a polypyrrole electrode modified by a nickel phthalocyanine complex. Application to their HPLC separation and to their FIA system detections

A polypyrrole electrode modified with a tetrasulfonated nickel(II) phthalocyanine complex (GCE/PPy/NiPcTs) was used as amperometric electrochemical detector in a flow injection system, in order to determine some antioxidants in foods. The lather were separated by HPLC and detected at the modified electrode. Previous investigations carried out in our laboratory employed this electrode and cyclic voltammetry (CV), obtaining excellent results, due to an electrocatalytic effect on the oxidation of certain alimentary antioxidants, such tert-butylhydroquinone (TBHQ), 3-tert-butyl-4-hydroxyanisole (BHA) and propylgallate (PG). In order to obtain good separation, the chromatographic conditions were optimised. The geometry of the flow injection analysis (FIA) circuit and the reproducibility of the results were also optimised and, finally, the linear relationship between the signal and the concentration was verified. The proposed procedure is more precise and accurate than the conventional voltammetry methods. These results offer new analytical possibilities to this type of modified electrodes. The developed methods were applied to the determination of these antioxidants in commercial food.     

模拟退火神经网络用于药物液相色谱梯度分离条件的优化

模拟退火神经网络用于药物液相色谱梯度分离条件的优化。使用均匀设计法以乙腈在线性梯度展开时的初始浓度和线性梯度的斜率为优化参数,对六种药物混合体系进行优化。采用退火神经网络方法建立了有效的分离条件预测模型。对神经网络模型所预测的最佳分离条件进行试验,分离结果满意。模拟退火神经网络可有效地用于药物液相色谱分离条件的优化。     

高效液相色谱法测定食品中抗氧化剂BHA,BHT,PG

 用反相高效液相色谱法同时测定了食品中抗氧化剂丁基羟基茴香醚（ＢＨＡ）、二丁基羟基甲苯（ＢＨＴ）和焦性没食子酸丙酯（ＰＧ）。样品用正己烷提取，氮气吹干，水－乙醇（１４，Ｖ／Ｖ）溶解残留物，经０．５μｍ滤膜过滤，直接进样。方法简便、快速、回收率高、重现性好。     

Voltammetric Behavior and Determination of Tocopherol in Vegetable Oils at a Polypyrrole Modified Electrode

The voltammetric behavior of α‐tocopherol in the presence of vegetable oil is studied at a polypyrrole modified Pt electrode in a 1,2‐dichloroethane‐ethanol medium with cyclic voltammetry. Cyclic voltammogram of α‐tocopherol showed a well‐defined oxidation peak; the peak potential shifting toward less positive and a much higher peak current obtained at a polypyrrole modified electrode than that obtained at the unmodified Pt electrode. An electroanalytical method for the determination of α‐tocopherol based on its electrochemical oxidation at the polypyrrole modified Pt electrode is developed. Using differential pulse voltammetry, the peak currents were found to increase linearly with the α‐tocopherol concentration over the range of 5.0 to 300 μM, with a sensitivity of 5.38×10^?2 A L mol^?1 and the limit of detection of 1.5 μM (S/N=3), the detection time being about 90 s for each assay. The interference of other synthetic antioxidants such as TBHQ, BHA and BHT to the analysis of α‐tocopherol was investigated. The developed method is applied to the quantification of tocopherols in six vegetable oils, showing that the results are in good agreement with those by HPLC method.     

二氧化硅纳米均孔膜修饰电极检测化妆水中的抗氧化剂

制备了氧化铟锡(ITO)电极支撑的二氧化硅纳米均孔膜,保留胶束模板在纳米通道内,得到二氧化硅和胶束复合膜修饰的电极,并将其用于化妆品中丁基羟基苯甲醚和叔丁基对苯二酚的电化学检测。该均孔膜孔径2.3 nm,具有精确的尺寸筛分能力;胶束尾部的碳氢长链提供了疏水微环境,能够在水溶液中快速萃取和富集疏水有机分子。该电极对两种抗氧化剂的检测均获得了较好的灵敏度、线性范围和检测限,加标回收率分别为96.4%和104%,表明该电化学传感器具有一定的应用潜力。     

Separation and Determination of Phenolic Antioxidants by HPLC with Surfactant/n‐Propanol Mobile Phases

The influence of cationic and anionic surfactants and short‐chain alcohols in the mobile phase on the retention of five antioxidants has been studied. The solutes chosen were butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and propyl, octyl, and dodecyl gallates (PG, OG, DG).The surfactants were hexadecyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), and n‐propanol (PrOH) was the selected alcohol. A simple isocratic reversed‐phase method for the antioxidant determination is proposed. Separation of five primary antioxidants takes 18 min with the mobile phase SDS 0.10 M/H₃PO₄ 0.01 M/PrOH 30%. Variation of the percentage of alcohol in the mobile phase permits optimization of the retention times of the antioxidants. Detection limits in the pg range were obtained for the all solutes. The method was used to determine the antioxidants in olive oil at three different levels, giving mean recoveries close to 100% for all the solutes (BHA 102%, PG 99%, OG 99%, DG 99%) except BHT (84%).     

By-products from fruit processing

The oxidative stability of soybean oil added of extracts from by-products generated in the pulp processing of mango (CM), Barbados cherry (CB) and guava (CG), as well as the combination of these extracts with the antioxidants butylated hydroxytoluene (BHT) and tertiary butylhydroquinone (TBHQ), were evaluated by pressurized differential scanning calorimetry (P-DSC) and Rancimat methods. Among the extracts, that obtained from CB showed the highest content of total extractible phenolic. Soybean oil added of CM extract showed greater (p < 0.05) oxidative stability in Rancimat analysis, while by P-DSC method CB was the extract more effective (p < 0.05) to protect soybean oil. Soybean oil added of CB extract showed higher (p < 0.05) OIT values compared to those added of CM, CG and synthetic antioxidants BHT and TBHQ. The combination of CB, CM and CG extracts with TBHQ showed synergistic effects, while CM and CB combined with BHT showed antagonistic effect on oxidative stability in soybean oil. The OIT results obtained from analysis by P-DSC and the OSI results obtained by Rancimat showed Pearson moderate correlation (r = 0.42). These results suggest the CB, CM and CG extracts as good source of antioxidant compounds with potential for combined application with synthetic antioxidants to prevent oxidation in soybean oil.